The present invention relates to an arm for a motor-vehicle independent suspension system. According to a further aspect, the present invention relates to a motor-vehicle independent suspension system comprising an arm of the above-mentioned type.
For a better understanding of the prior art on the subject in question and of the problems relating thereto, a general outline of motor-vehicle suspension systems and of the requirements which they are called upon to satisfy will be provided first of all.
As is known, the system for the suspension of the wheels of a motor vehicle is the set of components which connect the wheels to the body of the vehicle, controlling their relative displacement in response to the forces applied.
The suspension system may be considered simply as a resilient element having characteristics of stiffness, in relation to all six degrees of freedom existing between the wheels and the body of the vehicle, such as to satisfy predetermined requirements such as, for example, the capability to permit large displacements of the wheels in a substantially vertical direction. A suspension system for a road vehicle of recent design must perform mainly the following two functions:                connecting the wheels to the vehicle body in a resiliently compliant manner in order to insulate the occupants from roughness and unevenness in the road surface, and        reacting in a sufficiently stiff manner to the forces acting upon the wheels, particularly during steering and braking, to ensure a quick and reliable response to the driver's commands.        
The simultaneous presence of these conflicting requirements for resilient compliance and stiffness obliges suspension-system manufacturers to seek compromise solutions but these succeed only with difficulty in satisfying in an acceptable manner both of these requirements for occupant comfort and control of vehicle response.